Tom Booth noted that eye color presents a separate puzzle: the vitamin D story doesn’t explain why blue eyes, which have been present in some European populations since at least the Mesolithic, might have been advantageous. Blue eyes do not significantly improve vitamin D synthesis. The selective advantage of light eye color, if there is one, remains unclear — sexual selection has been proposed but not established.
What the Cheddar Man results contributed to this discussion was a well-dated data point: a specific individual, living in Britain around 10,000 years ago, carrying the genetic signature of the Western Hunter-Gatherer population, with predicted dark skin and blue or blue-green eyes. He is one piece of a larger picture being assembled across Europe, one ancient genome at a time.
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## The 2019 Paper and What It Confirmed
The 2019 Nature Ecology and Evolution paper — “Ancient genomes indicate population replacement in Early Neolithic Britain” by Brace, Diekmann, Booth, and their colleagues — placed the Cheddar Man genome in a larger analytical framework. The paper analyzed multiple ancient British genomes, spanning from the Mesolithic through the Neolithic, to characterize the population changes associated with the arrival of farming in Britain.
The findings confirmed what earlier studies had suggested: the transition to farming in Britain, which occurred around 4000 BCE, was accompanied by a near-complete replacement of the earlier hunter-gatherer population. The Neolithic farmers who brought agriculture to Britain were genetically distinct from the Western Hunter-Gatherers — they were descended primarily from populations with roots in the Aegean region, who had expanded through Europe following the development of agriculture in the Middle East.